MRI features in atypical idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) primarily affects obese women of reproductive age. However, IIH can also occur in individuals outside this typical demographic, where it is associated with a more severe clinical course and poorer visual outcome. Characteristic features of IIH have been identified on cerebral MRI but have not been systematically studied in atypical patient subgroups.

This retrospective cohort study investigated the prevalence of MRI features of IIH across the following subgroups: males, individuals with normal BMI (< 26 kg/m²), and patients diagnosed above the age of 45. The presence of empty sella (ES), posterior globe flattening (PGF), optic nerve sheath distension (ONSD), optic nerve tortuosity (ONT), transverse sinus stenosis (TSS), DWI-hyperintensity of the optic nerve head (ONH) and ONH-contrast enhancement were evaluated on MRI. The relationship between MRI features and the visual prognosis was investigated.

The study included 172 patients. ES was most frequent with 87%, followed by ONSD in 60%, TSS in 46%, ONT in 39% and PGF in 37%. ONH-DWI hyperintensity was present in 35%, and ONH-contrast enhancement in 22%. The prevalence of MRI features did not significantly differ across demographic subgroups and between atypical and typical IIH. Regression models did not indicate associations between MRI features and visual outcomes.

MRI features of IIH were equally prevalent in typical and atypical demographics. These findings suggest a consistent radiological presentation of IIH across demographic profiles, indicating a shared imaging phenotype regardless of atypical clinical characteristics. Limitations related to the retrospective design warrant future prospective studies.

Question Do MRI features of IIH differ across demographic subgroups (males, non-obese and older patients) and are they associated with visual outcomes? Findings MRI features of IIH were equally prevalent in typical and atypical patients; however, no significant association between imaging findings and visual outcome was observed. Clinical relevance While MRI supports the diagnosis of IIH across demographic subgroups, established imaging features do not seem to aid in identifying patients at risk of visual deterioration.